Plan year-by-year Roth conversions that fill your tax bracket, track the 5-year unlock schedule, and compare total tax against early withdrawals with the 10% penalty.
Your current pre-tax Traditional 401(k) / IRA balance — the money you'll convert to Roth.
Your age today. A conversion made at 63 or later sets your Medicare premiums two years afterwards, so the ladder flags any year that would push you past an IRMAA threshold.
W-2 wages, interest, and other ordinary income each year. It stacks under your conversions and uses up bracket room.
How much you plan to withdraw from unlocked Roth basis each year in early retirement.
How many years you'll make conversions. Each conversion becomes penalty-free 5 tax years after it's made.
Expected annual return on the Traditional balance that hasn't been converted yet.
Your year-9 conversion (at age 63) leaves only $42,500 of room before an IRMAA threshold. Crossing it would add about $1,148 to your Medicare premiums at age 65 — IRMAA is a cliff, so one dollar over costs the whole tier.
If you stop working before those premiums start, file Form SSA-44 — retirement is a qualifying life-changing event, and it lets Social Security use your current income instead of the two-year-old figure. It is one of the most valuable forms in retirement planning and one of the least used. MAGI here is estimated as other income plus the conversion; it excludes capital gains and the Social Security taxation formula, so treat this as a flag to investigate rather than a filing-grade number.
| Period | Traditional Balance | Unlocked Roth Basis | Cumulative Tax Paid |
|---|---|---|---|
| 1 | $485K | $0 | $5.4K |
| 2 | $469K | $0 | $11K |
| 3 | $453K | $0 | $16K |
| 4 | $434K | $0 | $22K |
| 5 | $415K | $0 | $27K |
| 6 | $394K | $47K | $32K |
| 7 | $372K | $93K | $38K |
| 8 | $349K | $140K | $43K |
| 9 | $323K | $186K | $49K |
| 10 | $296K | $233K | $54K |
| 11 | $267K | $279K | $60K |
| 12 | $236K | $326K | $65K |
| 13 | $203K | $372K | $70K |
| 14 | $167K | $419K | $76K |
| 15 | $129K | $465K | $81K |
| 16 | $138K | $512K | $81K |
| 17 | $148K | $558K | $81K |
| 18 | $158K | $605K | $81K |
| 19 | $169K | $651K | $81K |
| 20 | $181K | $698K | $81K |
Federal income tax only — no state tax, capital gains, or ACA subsidy effects. Medicare IRMAA thresholds are checked for conversions made at 63 or later, estimating income as other income plus the conversion; capital gains and the Social Security taxation formula are outside that estimate. 2026brackets and standard deduction are held constant across all ladder years. Conversions are taxed as ordinary income; each conversion's principal is penalty-free 5 tax years after it's made. Growth inside the Roth and Traditional accounts is not modeled as withdrawable basis. Investment returns are not guaranteed. Not tax or financial advice.